socket编程原理（七）

t sockaddr_in serv_addr;

if ((servrec = getservbyname(servicename, "tcp")) == NULL) {

return(-1);

}

bzero((char *)&Mysock, sizeof(Sockets));

Mysock.Port = servrec->s_port; /* Service Port in Network Byte Order */

if((mainsock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {

return(-2);

}

bzero((char *)&serv_addr, sizeof(serv_addr));

serv_addr.sin_family = AF_INET;

serv_addr.sin_addr.s_addr = htonl(INADDR_ANY); /* 任意网络接口 */

serv_addr.sin_port = servrec->s_port;

if (bind(mainsock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {

close(mainsock);

return(-3);

}

if (listen(mainsock, 5) == -1) { /* 将主动套接字变为被动套接字，准备好接收连接 */

close(mainsock);

return(-4);

}

/* Set this socket as a Non-blocking socket. */

if (ioctl(mainsock, FIONBIO, &flag) == -1) {

close(mainsock);

return(-5);

}

Mysock.DaemonSock = mainsock;

FD_SET(mainsock, &Mysock.readfds); /* 申明对主套接字"可读"感兴趣 */

FD_SET(mainsock, &Mysock.exceptfds); /* 申明对主套接字上例外事件感兴趣 */

return(1);

}

void CloseMainSock()

/* 关闭主套接字，并清除对它上面事件的申明。在程序结束前关闭主套接字是一个好习惯 */

{

close(Mysock.DaemonSock);

FD_CLR(Mysock.DaemonSock, &Mysock.readfds);

FD_CLR(Mysock.DaemonSock, &Mysock.exceptfds);

}

int CreateConnection(struct in_addr *sin_addr)

/* Create a Connection to remote host which IP address is in sin_addr.

Param: sin_addr indicates the IP address in Network Byte Order.

if succeed return the socket number which indicates this connection,

else return error code (<0) */

{

struct sockaddr_in server; /* server address */

int tmpsock, flag=1, i;

if ((tmpsock = socket(AF_INET, SOCK_STREAM, 0)) < 0)

return(-1);

server.sin_family = AF_INET;

server.sin_port = Mysock.Port;

server.sin_addr.s_addr = sin_addr->s_addr;

/* Set this socket as a Non-blocking socket. */

if (ioctl(tmpsock, FIONBIO, &flag) == -1) {

close(tmpsock);

return(-2);

}

/* Connect to the server. */

if (connect(tmpsock, (struct sockaddr *)&server, sizeof(server)) < 0) {

if ((errno != EWOULDBLOCK) && (errno != EINPROGRESS)) {

/* 如果错误代码是EWOULDBLOCK和EINPROGRESS，则不用关闭套接字，因为系统将在之后继续为套接字建立连接，连接是否建立成功可用select()函数来检测套接字是否"可写"来确定。*/

close(tmpsock);

return(-3); /* Connect error. */

}

}

FD_SET(tmpsock, &Mysock.readfds);

FD_SET(tmpsock, &Mysock.writefds);

FD_SET(tmpsock, &Mysock.exceptfds);

i = 0;

while (Mysock.Sockets[i] != 0) i++; /* look for a blank sockets position */

if (i >= 64) {

close(tmpsock);

return(-4); /* too many connections */

}

Mysock.Sockets[i] = tmpsock;

Mysock.SockNum++;

return(i);

}

int AcceptConnection(struct in_addr *IPaddr)

/* Accept a connection. If succeed, return the data sockets number, else return -1. */

{

int newsock, len, flag=1, i;

struct sockaddr_in addr;

len = sizeof(addr);

bzero((char *)&addr, len);<